Go-alpha, a GTP-binding protein of unknown function, present in relative high concentration in brain, has been cloned in this laboratory and expressed in E. coli. Go produced in E. coli, however, aggregated making purification and assessment of its GTPase activity impossible. It was proposed that aggregation might be due to properties of E. coli and that the gene expressed in a eukaryotic system capable of post-translation modifications, might produce nonaggregated Go protein. The baculovirus (BCV) cloning system uses insect (Spodoptera frugiperda = Sf-9) cells infected with virus containing the gene of interest to express large amounts of foreign proteins off of a viral promoter. The insect cells are capable of glycosylation, leader sequence cleavage, phosphorylation and extracellular secretion. Hence, the purpose of the following work was to express Go in the BCV system to see whether a nonaggregated, functional protein could be obtained.